July in Cotulla is the sunniest month of the year. In July, the weather in Cotulla is typically hot. Average daily high temperature in July is about 37 degrees above zero. On average, Cotulla has 18 sunny, 7 partly cloudy, and 6 rainy days in July. The rains are usually heavy. July as well as May, June, August, and September is considered the most uncomfortable time to visit Cotulla.